The effect of varying cutting frequencies on the yield of hardy and nonhardy alfalfa (Medicago sativaL. ) and red clover (Trifolium pratenseL.) cultivars and subsequent oat (Avena sativaL. ) production was studied. Analysis for nitrogen (N) in the oat crop provided an indirect measurement of residual N fixed by the preceding legume crop. Red clover produced the greatest yield and supported the greatest oat yield. Red clover and nonhardy alfalfa growth resulted in the greatest residual N (oat yield x N concentration). Highly significant linear responses between cutting frequency and residual N were found for hardy alfalfa and red clover, while no relationship was evident for nonhardy alfalfa. The data suggest that nonhardy alfalfa and new cultivars of red clover have the capacity to supply more N than hardy alfalfa.